The drive for alternative energy has increased development of photo-voltaic (“PV”) power plants that may be connected to the electrical grid. A PV power plant has a power converter which converts direct current voltage from a PV source, such as solar panels, to alternating current voltage suitable for connection to the electrical grid. As more and more large-scale PV power plants are put into operation due to increasing green energy requirements, utilities are applying more and more regulations on PV power plants, since the quality and stability of a power system may be affected by the installation of PV power plants.
Recently, as the capacity of single PV power plants has increased rapidly, the emphasis on high PV voltage installations is getting higher because such installations can lower the installation cost. An open circuit voltage of about 1000V is currently desired from many PV installers. Facing this challenge, PV plant manufacturers have combined many different PV voltage sources to achieve high voltages. Such high voltages also require relatively more expensive high voltage components in order to prevent breakdown of components from the high voltage. Of course, the PV plants also require protection of electronic components in the form of circuits that break the voltage connection when voltage over a set threshold voltage is encountered from the voltage sources.
Currently, source circuits are individually fused and then commonly coupled on the load or inverter side of the fuses. Load-break disconnect switches and DC contactors are required to break the combined circuit. However, the cost of such high power components capable of breaking high DC currents at relatively high voltages is prohibitive. Thus, it is desired for cost effective combination of PV sources with an effective break for higher voltage PV arrays.